Instant Coffee - Production

Production

As with regular coffee, the green coffee bean itself is first roasted to bring out flavour and aroma. Rotating cylinders containing the green beans and hot combustion gases are used in most roasting plants. When the bean temperature reaches 165 °C the roasting begins, accompanied by a popping sound similar to that produced by popcorn. These batch cylinders take about 8–15 minutes to complete roasting with about 25–75% efficiency. Coffee roasting using a fluidized bed only takes from thirty seconds to four minutes, and it operates at lower temperatures which allows greater retention of the coffee bean aroma and flavor.

The beans are then ground finely. Grinding reduces the beans to 0.5–1.1-millimetre (0.020–0.043 in) pieces in order to allow the coffee to be put in solution with water for the drying stage. Sets of scored rollers designed to crush rather than cut the bean are used.

Once roasted and ground, the coffee is dissolved in water. This stage is called extraction. Water is added in 5–10 percolation columns at temperatures of 155 to 180 °C; this concentrates the coffee solution to about 15–30% coffee by mass. This may be further concentrated before the drying process begins by either vacuum evaporation or freeze concentration.